A decade of change in the uptake of parathyroidectomy in England and Wales

INTRODUCTION

Since the late 1990s, a number of factors have reduced the threshold for parathyroidectomy in patients with primary hyperparathyroidism. This study examined whether this has translated into increased numbers of parathyroid operations over the last decade.

METHODS

A retrospective analysis was performed of the Patient Episode Database for Wales and English Hospital Episode Statistics annual data from 2000 to 2010 for parathyroidectomy admissions per 100,000 population. Statistical analysis was by linear regression.

RESULTS

Between 2000 and 2010 there were 24,247 parathyroid operations in England and Wales (0.005% of the population), with 3 times as many women treated as men. Overall, incidence of parathyroidectomy rose from 3.3/100,000 population in 2000 to 5.8/100,000 in 2010 (p<0.0001). In England, it increased from 3.3/100,000 population to 5.8/100,000 and in Wales, it increased from 2.4/100,000 population to 4.6/100,000. Despite similar population demographics, the difference in the rate of change between England and Wales was significant (p<0.05). Uptake also varied according to age; in those aged 0-14 years, incidence of parathyroidectomy remained static whereas in all other age groups, uptake of parathyroidectomy increased significantly from 2000 to 2010. Most notably, surgical intervention in those aged 60-74 and >75 years nearly doubled over the decade (p<0.0001).

CONCLUSIONS

The incidence of parathyroidectomy in adults has increased significantly in the last decade in England and Wales. This likely reflects changes in population demography, available guidelines, lower threshold for referral, changing surgical approach and the realisation that surgical morbidity is now infrequent.

Temperature alters the relative abundance and population growth rates of species within the Dendroctonus frontalis (Coleoptera: Curculionidae) community

Temperature has strong effects on metabolic processes of individuals and demographics of populations, but effects on ecological communities are not well known. Many economically and ecologically important pest species have obligate associations with other organisms; therefore, effects of temperature on these species might be mediated by strong interactions. The southern pine beetle (Dendroctonus frontalis Zimmermann) harbors a rich community of phoretic mites and fungi that are linked by many strong direct and indirect interactions, providing multiple pathways for temperature to affect the system. We tested the effects of temperature on this community by manipulating communities within naturally infested sections of pine trees. Direct effects of temperature on component species were conspicuous and sometimes predictable based on single-species physiology, but there were also strong indirect effects of temperature via alteration of species interactions that could not have been predicted based on autecological temperature responses. Climatic variation, including directional warming, will likely influence ecological systems through direct physiological effects as well as indirect effects through species interactions.

A longitudinal study into the new and long-term use of self-monitoring blood glucose strips in the UK

AIMS

To determine the impact of self-monitoring blood glucose (SMBG) strip use in patients with type 2 diabetes in the UK.

METHODS

The study period was April 1, 2004 to July 31, 2005. Data from primary care was extracted from The Health Improvement Network database. Patients identified with diabetes and matching the inclusion criteria were defined as new users of SMBG, prevalent users, or non-users. Patients were also defined as treated with insulin, with oral agents (OA), or not pharmacologically treated. Change in glycosylated hemoglobin (HbA(1c)) at baseline and after 12 months was compared.

RESULTS

2559 patients met the inclusion criteria. For new users, HbA(1c) fell by 0.59% (P=0.399) for those treated with insulin, 1.52% (P<0.001) for those treated with OA, and 0.51% (P<0.001) for no treatment. In prevalent users, changes were 0.31% (P<0.001), 0.34% (P<0.001), and 0.09% (P=0.456), respectively. In non-users, changes were 0.28% (P=0.618), 0.42% (P<0.001), and an increase of 0.05% (P=0.043), respectively. A significant decrease in mean HbA(1c) was associated with increasing strip use in OA patients newly initiated on strips.

CONCLUSION

This observational study showed a significant decrease in HbA(1c) for new users of SMBG treated either non-pharmacologically or with OA, and for prevalent users treated with insulin or OA. Reduced HbA(1c) with increasing strip use was observed but was only significant for OA-treated new users. This suggests that SMBG use has a role in the treatment of non-insulin treated patients with type 2 diabetes.

Insulin therapy in type 2 diabetes: insulin analogue mix 50, a potential role in reducing postprandial hyperglycaemia and cardiovascular disease

IMPORTANCE OF THE FIELD

Postprandial hyperglycaemia is becoming topical, with studies suggesting a link to cardiovascular disease. Recently, a number of new therapies for the treatment of type 2 diabetes have become available.

AREAS COVERED IN THIS REVIEW

This review looks at the evidence for the potential role of insulin analogue mix 50 to reduce postprandial hyperglycaemia and cardiovascular disease.

SEARCH STRATEGY

Medline and Embase databases were searched using the MeSH terms to identify relevant studies from 1980 to 2009. Both original articles and reviews were extracted. Published reference lists were also examined. MeSH terms used for literature searching: human insulins, insulin analogues, insulin analogue mix 50, glycaemia, postprandial glucose, fasting glucose, type 2 diabetes, type 1 diabetes, cardiovascular disease.

WHAT THE READER WILL GAIN

The reader is presented with evidence discussing the importance of postprandial hyperglycaemia and studies comparing different insulin regimes and in particular insulin analogue mix 50 and its potential to reduce postprandial glucose surges and reduce cardiovascular disease.

TAKE-HOME MESSAGE

Insulin analogue mix 50 is a viable therapeutic option in a sub-group of patients with type 2 diabetes.

Characterization and utilization of microsatellite loci in the New World screwworm fly, Cochliomyia hominivorax

New World screwworm populations in North and Central America have been the targets of virtually continuous eradication attempts by sterile insect technique (SIT) since the 1950s. Nevertheless, in some areas, such as Jamaica, SIT control programmes have failed. Reasons for the failure of SIT-based control programmes in some locations are unknown, but it has been hypothesized that failure may be related to mating incompatibility between sterile and wild fly populations or to the existence of sexually incompatible cryptic species. This paper outlines the development of a suite of four new microsatellite loci which can be used to study intra-specific relationships between populations of Cochliomyia hominivorax from the Caribbean and South America, which represent those populations involved in, or earmarked for, forthcoming SIT control. Cross-amplification with the secondary screwworm, Cochliomyia macellaria, was also successful with three of the new loci. We present results which suggest that populations from Trinidad and Jamaica form distinct groupings of flies and that C. hominivorax from Trinidad appears particularly distinct.

Rosiglitazone produces a greater reduction in circulating platelet activity compared with gliclazide in patients with type 2 diabetes mellitus--an effect probably mediated by direct platelet PPARgamma activation

AIMS

Type 2 diabetes mellitus (T2DM) is associated with enhanced platelet activation. We conducted a randomised double-blind study to compare the effects of combination metformin and rosiglitazone or metformin and gliclazide therapy on platelet function in persons with T2DM.

METHODS

Fifty subjects on metformin monotherapy received either rosiglitazone 4 mg or gliclazide 80 mg. HbA1c, HOMA-R, markers of platelet activation, inflammation, endothelial activation and oxidative stress were measured at baseline and after 24 weeks of treatment. Separate in vitro platelet function studies were conducted on platelets pre-incubated with rosiglitazone and gliclazide.

RESULTS

A significantly greater reduction in platelet aggregation was observed in the rosiglitazone treated group compared to gliclazide. HbA1c and markers of endothelial activation were reduced to a similar extent in both groups. A significant reduction in HOMA-R, markers of inflammation and oxidative stress was only observed with rosiglitazone. Reduction in platelet aggregation with rosiglitazone correlated with reduction in oxidative stress. In the in vitro study, rosiglitazone produced significantly greater reduction in platelet aggregation compared with gliclazide.

CONCLUSION

Greater reduction in platelet activity observed with rosiglitazone may be related to reduced oxidative stress and a possible direct PPARgamma mediated effect on platelet function.

Diuretic-induced hypokalaemia in patients with hypertension

We describe a 55 year-old woman with longstanding hypertension who developed hypokalaemia following diuretic treatment. Investigations revealed primary hyperaldosteronism due to an adrenal adenoma, and normal blood pressure was restored after surgical removal of the tumour. Primary hyperaldosteronism is a potentially curable cause of hypertension and should be considered in hypertensive patients who present with diuretic - induced hypokalaemia.

Peripheral cytokine expression in autoimmune thyroiditis: effects of in vitro modulation by rosiglitazone and dexamethasone

BACKGROUND

In Hashimoto's thyroiditis (HT), there is evidence for activation of peripheral T-lymphocytes that predominantly express a T helper 1 (T(H)1) cytokine bias. However, the immunomodulatory factors involved in regulating this response have so far received scant attention. In this study, we examine the effects of the glucocorticoid, dexamethasone, and the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand, rosiglitazone on the expression of interferon (IFN)-gamma (T(H)1) and interleukin (IL)-4 (T(H)2) by activated peripheral CD4(+) and CD8(+) lymphocytes in patients with HT (n = 10) and healthy control subjects (n = 12).

METHODS

Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with phorbolmyristate acetate (PMA) and ionomycin in the presence or absence of varying doses of dexamethasone and rosiglitazone (0.01 microM, 1.0 microM, and 100 microM). Cytokine expression was determined by flow cytometry.

RESULTS

CD4(+) and CD8(+) IFN-gamma expression was greater in HT than controls (14.87 versus 9.25; p < 0.05 and 21.34 versus 10.16; p < 0.01, respectively). A dose-dependent inhibition of IFN-gamma expression was seen with dexamethasone and rosiglitazone. Inhibition of CD4(+) and CD8(+) IFN-gamma expression with both dexamethasone and rosiglitazone was greater in control subjects than in patients (p < 0.05). There was no significant difference in IL-4 expression between patients and control groups and its expression remained unaffected by either compound.

CONCLUSIONS

We show that CD4(+) and CD8(+) T lymphocytes from HT patients express a type 1 cytokine bias that is significantly more resistant to in vitro modulation by rosiglitazone and dexamethasone. Further studies are needed to clarify if this resistance plays a role in the pathogenesis of autoimmune thyroid disease (AITD).

Prolonged deterioration of endothelial dysfunction in response to postprandial lipaemia is attenuated by vitamin C in Type 2 diabetes

BACKGROUND

Endothelial dysfunction (ED) has been described in Type 2 diabetes (T2DM). We have described previously a diminution of flow-mediated arterial dilatation and, by implication, further ED in T2DM in response to postprandial lipaemia (PPL) at 4 h. This is possibly mediated by oxidative stress/alteration of the nitric oxide (NO) pathway. T2DM subjects tend to exhibit both exaggerated and prolonged PPL. We therefore studied the relationship of PPL to the duration of ED in T2DM subjects and oxidative stress with or without the antioxidant, vitamin C.

METHODS

Twenty subjects with T2DM with moderate glycaemic control (mean HbA1c 8.4%) were studied. After an overnight fast, all subjects consumed a standard fat meal. Endothelial function (EF), lipid profiles, and venous free radicals were measured in the fasting, peak lipaemic phase (4 h) and postprandially to 8 h. The study was repeated in a double-blinded manner with placebo, vitamin C (1 g) therapy for 2 days prior to re-testing and with the fat meal. Oxidative stress was assessed by lipid-derived free radicals in plasma, ex vivo by electron paramagnetic resonance spectroscopy (EPR) and by markers of lipid peroxidation (TBARS). Endothelial function was assessed by flow-mediated vasodilatation (FMD) of the brachial artery.

RESULTS

There was a significant decrease in endothelial function in response to PPL from baseline (B) 1.3 +/- 1.3% to 4 h 0.22 +/- 1.1% (P < 0.05) and 8 h 0.7 +/- 0.9% (P < 0.05) (mean +/- sem). The endothelial dysfunction seen was attenuated at each time point with vitamin C. Baseline EF with vitamin C changed from (fasting) 3.8 +/- 0.9-2.8 +/- 0.8 (at 4 h) and 2.9 +/- 1.3 (at 8 h) in response to PPL. Vitamin C attenuated postprandial (PP) oxidative stress significantly only at the 4-h time point [301.1 +/- 118 (B) to 224.7 +/- 72 P < 0.05] and not at 8 h 301.1 +/- 118 (B) to 260 +/- 183 (P = NS). There were no changes with placebo treatment in any variable. PPL was associated with a PP rise in TG levels (in mmol/l) from (B) 1.8 +/- 1 to 2.7 +/- 1 at 4 h and 1.95 +/- 1.2 at 8 h (P = 0.0002 and 0.33, respectively).

CONCLUSION

PPL is associated with prolonged endothelial dysfunction for at least 8 h after a fatty meal. Vitamin C treatment improves endothelial dysfunction at all time points and attenuates PPL-induced oxidative stress. This highlights the importance of low-fat meals in T2DM and suggests a role for vitamin C therapy to improve endothelial function during meal ingestion.

Long-term remission following withdrawal of dopamine agonist therapy in subjects with microprolactinomas

OBJECTIVE

Reports suggest that up to 70% of patients with microprolactinomas treated with dopamine agonist therapy may achieve long-term normoprolactinaemic remission following drug withdrawal. Yet, there is no consensus on the duration of therapy nor is therapeutic interruption universally practised. We have assessed remission rates in a large cohort of treatment-naive subjects with microprolactinomas. Subjects received dopamine agonist (DA) therapy with either cabergoline or bromocriptine for a period of 2 to 3 years in the majority of cases, followed by a trial of treatment withdrawal.

DESIGN

Retrospective analysis of clinic records of 89 patients (mean age 32.7 +/- 8.4 years, 84 women and 5 men) who had received either cabergoline (n = 67) (0.5-3 mg weekly) or bromocriptine (n = 22) (2.5-10 mg daily) for a mean duration of 3.1 years.

RESULTS

Following withdrawal of therapy, 57 subjects developed recurrence (64%) and the mean time to recurrence was 9.6 months (range 1-44 months), while 32 subjects (36%) remained in remission beyond 1 year (mean 3.6 years, range 1-7 years). There was no difference in remission rates between subjects treated with cabergoline (n = 21) and bromocriptine (n = 11), but a direct relationship between pretreatment prolactin concentration and risk of recurrent symptomatic hyperprolactinaemia was observed. No subjects developed clinical features to suggest tumour expansion following therapeutic discontinuation.

CONCLUSIONS

This study confirms that abrupt withdrawal of chronic dopamine agonist therapy, following 2 to 3 years of treatment is safe and associated with long-term remission in 30-40% of subjects with microprolactinomas. This therapeutic strategy is convenient and applicable in clinical practice.

"Osler's phenomenon": misdiagnosing Cushing's syndrome

The clinical manifestations of Cushing's syndrome can be quite variable and are frequently mistaken, with consequent delayed diagnosis and significant morbidity and mortality. Harvey Cushing described the typical signs and symptoms of Cushing's syndrome but unfortunately attributed the features to myxoedema. The first typical description of a patient with Cushing's syndrome was probably made by Sir William Osler in 1898. Thus delay or misdiagnosis with consequent high morbidity and mortality exemplifies the history of Cushing's syndrome. Four cases of Cushing's syndrome are described that were associated with deteriorating morbidity because of the considerable delay from first presentation to a secondary care physician to eventual diagnosis. The clinical diagnosis was delayed in all the four patients, although they had symptoms and signs that were missed by a number of primary and secondary care physicians. Trans-sphenoidal surgery resulted in biochemical cure as well as improvement in the accompanying co-morbidity. Although still rare, the prevalence of Cushing's syndrome is increasing. Increasing clinical awareness and the use of appropriate screening tests should facilitate earlier diagnosis with reduced morbidity and mortality. Although the syndrome is named after Harvey Cushing, Sir William Osler was probably the first to describe it. Therefore, in deference to Osler's contribution to Cushing's syndrome and the work of Harvey Cushing, it is suggested that to the list of the other eponymous conditions of Osler-Weber-Rendu and Osler's nodes, should be added the delay or misdiagnosis of Cushing's syndrome-"Osler's phenomenon".

The TSH response to domperidone reflects the biological activity of prolactin in macroprolactinaemia and hyperprolactinaemia

OBJECTIVE

To test the hypothesis that patients with hyperprolactinaemia due to biologically inactive macroprolactin will not show the characteristically increased dopaminergic inhibition of TSH release seen in patients with microprolactinomas secreting biologically active monomeric PRL.

DESIGN

Comparison of the TSH and PRL responses to dopamine antagonism with domperidone (10 mg i.v.) in patients with hyperprolactinaemia due to macroprolactinaemia or microprolactinomas.

PATIENTS

Twenty-two patients referred for the investigation of their hyperprolactinaemia were studied: 11 patients with macroprolactinaemia and 11 patients with hyperprolactinaemia due to microprolactinoma.

MEASUREMENTS

TSH and PRL levels were measured at baseline and 30 min following domperidone in both groups.

RESULTS

Patients with macroprolactinaemia showed normal TSH and PRL responses to dopamine antagonism whereas patients with microprolactinomas showed exaggerated TSH responses and reduced PRL responses. Although there was considerable overlap between the PRL responses in the two groups, there was very clear separation between the PRL/TSH response ratios (normal > 1.0) of 4.0 +/- 1.8 for the macroprolactinaemia group and 0.4 +/- 0.2 for the microprolactinoma group (P < 0.0001).

CONCLUSIONS

These data support the hypothesis that elevated circulating levels of macroprolactin, as opposed to biologically active monomeric PRL, do not exert increased positive feedback on the hypothalamic dopaminergic inhibition of TSH release.

The effects of depot long-acting somatostatin analog on central aortic pressure and arterial stiffness in acromegaly

Acromegaly is associated with increased cardiovascular risk. Although conventional risk factors such as glucose intolerance, hypertension, and dyslipidemia probably contribute, there may also be direct effects of GH/IGF-I excess on the vasculature. To study the effects of GH excess on the vasculature, we have assessed arterial stiffness in acromegalic subjects with and without active disease and have investigated the effects of Sandostatin LAR (OCT-LAR) on vascular function. Sixteen normotensive subjects with acromegaly (10 males and 6 females) and 8 healthy controls were studied. Of the acromegalic subjects, eight had active disease (group A), and eight were cured (GH < 2.5 mU/liter; group B). The three groups were age, sex, and blood pressure matched. Group A subjects were restudied after 3 and 6 months of OCT-LAR therapy. Arterial stiffness was assessed by analyzing central arterial pressure waveforms derived from measured radial artery waveforms. This allowed determination of the augmentation of central pressure and the augmentation index. Lipids, glucose, and IGF-I were also measured. Comparing the three groups (ANOVA; mean +/- SD), the augmentation index was higher in group A (28 +/- 12 vs. 12 +/- 13%; P < 0.01) but not in group B (22 +/- 7 vs. 12 +/- 13%; P = 0.60), compared with controls. IGF-I was higher in group A (50.3 +/- 21.2 nmol/liter; P < 0.01), compared with group B (22.5 +/- 8.9 nmol/liter) and controls (19.5 +/- 5.3 nmol/liter). On regression analysis, IGF-I concentration was identified as a strong independent predictor of the augmentation index (beta = 0.50; P = 0.007). There were no significant differences in aortic systolic pressure, aortic diastolic pressure, lipids, or glucose. Compared with baseline, OCT-LAR treatment resulted in a lowering of augmentation index at 3 months (20 +/- 15 vs. 28 +/- 12%; P < 0.05), but at 6 months (24 +/- 16%; P = 0.21) there was no significant change. IGF-I was reduced from 50.3 +/- 21.2 nmol/liter at baseline to 31.4 +/- 13.2 nmol/liter at 3 months (P < 0.05) and 26.6 +/- 15.8 nmol/liter at 6 months (P < 0.05). In conclusion, acromegaly is associated with changes in the central arterial pressure waveform, suggesting large artery stiffening. This may have important implications for cardiac morphology and performance in acromegaly as well as increasing the susceptibility to atheromatous disease. Large artery stiffness is reduced in cured acromegaly and partially reversed after pharmacological treatment of active disease.

Endothelial function and coagulant factors in growth hormone-treated hypopituitary adults receiving desmopressin

Although GH deficiency may underlie the increased cardiovascular risk in adult hypopituitarism, other coexisting hormonal deficiencies and/or unphysiological hormone replacement may contribute. L-Deamino-8-D-arginine (DDAVP), when administered parenterally, potentiates hemostasis by increasing plasma procoagulant factors. We investigated whether chronic intranasal DDAVP therapy influences clotting factors (plasma fibrinogen, factor VIII, and von Willebrand factor antigen) and endothelial function (flow-mediated dilation of the brachial artery) in 30 GH-treated hypopituitary subjects, including both DDAVP-treated subjects (group A) (mean age, 46 +/- 11 yr) and vasopressin-sufficient subjects (group B) (mean age, 47 +/- 16 yr). Fifteen healthy controls (group C) (mean age, 48 +/- 12 yr) were also studied. All hypopituitary patients were receiving stable GH replacement (median duration, 19 months). Comparing the three groups, concentrations of fibrinogen (mean +/- SD) (A, 3.3 +/- 1.0 g/liter vs. B, 3.5 +/- 0.9 vs. C, 2.6 +/- 0.8, P < 0.05), factor VIII (A, 130% +/- 30% vs. B, 128% +/- 30% vs. C, 104% +/- 35%, P < 0.05) and von Willebrand factor antigen (A, 124% +/- 35% vs. B, 134% +/- 45% vs. C, 93% +/- 36%, P < 0.05) were higher in hypopituitary subjects, compared with controls. However, there were no differences in clotting factors between groups A and B. Flow-mediated dilation did not differ significantly between the two hypopituitary groups (A, 5.9% +/- 2.0% vs. B, 4.7% +/- 1.6%) and was similar to that in the control group (C, 5.7% +/- 2.1%). In conclusion, although endothelium-dependent vasodilation is intact in GH-treated hypopituitary adults, elevated concentrations of hemostatic markers suggest the persistence of a prothrombotic tendency and endothelial dysfunction. Intranasal DDAVP does not appear to influence this proatherogenic profile in hypopituitary adults with vasopressin deficiency.

Increased central arterial stiffness in hypothyroidism

Hypothyroidism is associated with cardiovascular dysfunction. It is increasingly apparent that stiffening of central arteries may lead to increased afterload and cardiac dysfunction. We noninvasively studied the peripheral and central pressure waveforms in 12 untreated hypothyroid patients as well as in 12 age-, sex-, and body mass index-matched controls using the technique of pulse wave analysis from recordings at the radial artery. Indexes of arterial stiffness, augmentation index (AI) and augmentation of central arterial pressure (AG), were derived as well as time of travel of the reflected wave (TR), a direct estimate of aortic pulse wave velocity. At baseline, there were no significant differences between the 2 groups in brachial and aortic blood pressures. Hypothyroid patients had significantly higher AI than controls (mean +/- SEM[SCAP], 32.0 +/- 3.4% vs. 17.0 +/- 2.4%; P < 0.0005) even when corrected for heart rate (AI(C); 28.0 +/- 3.2% vs. 17.0 +/- 2.4%; P < 0.006) and AG (13.0 +/- 2.2 vs. 7.0 +/- 2.1 mm Hg; P < 0.03) together with a lower TR (132.0 +/- 4.1 vs. 142.0 +/- 1.5 msec; P < 0.03). After 6 months of therapy with T(4), all patients were euthyroid. AI(C) had decreased in the patient group (23.0 +/- 3.2% vs. 28.0 +/- 3.2%; P < 0.01) as had AG (9.0 +/- 1.5 vs. 13.0 +/- 2.2 mm Hg; P < 0.008), but TR was significantly higher (142.0 +/- 3.0 vs. 132.0 +/- 4.1 msec; P < 0.008). AI correlated with age in all groups (hypothyroid group: r = 0.937; P < 0.0005; control group: r = 0.804; P < 0.0005), but correlated with TSH level only among controls (r = 0.591; P < 0.05). This study confirms that hypothyroidism is associated with increased cardiovascular risk, as evidenced by increased augmentation of central aortic pressures and central arterial stiffness. Furthermore, these abnormalities are reversed after adequate T(4) replacement.

Effects of GH replacement on endothelial function and large-artery stiffness in GH-deficient adults: a randomized, double-blind, placebo-controlled study

OBJECTIVES

Hypopituitary adults with growth hormone deficiency (GHD) have an increased cardiovascular mortality, although the mechanisms remain unclear. Endothelial dysfunction, characterized by reduced nitric oxide (NO) bioavailability, is a key early event in atherogenesis and is associated with increased vascular smooth muscle tone and arterial stiffening.

DESIGN AND PATIENTS

In a randomized, double-blind, placebo-controlled study, we investigated the effects of GH replacement on endothelial function and large-artery stiffness in 32 GHD adults (19 males, 13 females) (age range 19-64 years) over a 6-month period. Thirty-two age- and sex-matched healthy controls were also studied.

MEASUREMENTS

Endothelial function was assessed using ultrasonic wall tracking to measure flow-mediated dilatation (FMD) of the brachial artery. Large artery stiffness was assessed by pulse wave analysis of the radial artery pressure waveform, allowing determination of the corresponding central arterial pressure waveform and derivation of the augmentation index. Fasting lipid profiles, glucose and insulin were also measured.

RESULTS

At baseline, FMD (mean +/- SD) was impaired in GH-deficient subjects vs. controls (3.4 +/- 2.3 vs. 5.7 +/- 2.0%, P < 0.0001), although endothelium-independent dilatation was similar. The augmentation index was higher in GH-deficient subjects vs. controls (23 +/- 12 vs. 14 +/- 14%, P < 0.01). GH-deficient subjects had higher LDL cholesterol (4.1 +/- 0.8 vs. 3.5 +/- 0.8 mmol/l, P < 0.01) and lower HDL cholesterol (1.1 +/- 0.3 vs. 1.4 +/- 0.4 mmol/l, P < 0.01). In GH-deficient subjects, there were inverse correlations between LDL cholesterol and FMD (r = -0.40, P < 0.05) and between FMD and the augmentation index (r = - 0.58, P < 0.01). Regression analysis identified FMD as an independent predictor of the augmentation index (P < 0.0001). In comparison with baseline, GH replacement resulted in an increase in FMD (5.0 +/- 2.6 vs. 2.8 +/- 1.9%, P < 0.01). There were decreases in central aortic systolic pressure (117 +/- 15 vs. 123 +/- 17 mmHg, P < 0.01), diastolic pressure (82 +/- 10 vs. 86 +/- 8 mmHg, P < 0.01) and the augmentation index (22 +/- 8% vs. 26 +/- 10%, P < 0.05) despite unchanged brachial pressure indices. LDL cholesterol also decreased (3.5 +/- 0.8 vs. 4.2 +/- 0.8 mmol/l, P < 0.01). There were no significant changes in the placebo group.

CONCLUSIONS

Adult GHD is associated with endothelial dysfunction and increased large-artery stiffness. An improvement in endothelial function and a reduction in arterial stiffness following GH replacement suggests an important therapeutic role for GH in reducing cardiovascular risk associated with adult GHD.

Effects of GH on lipid peroxidation and neutrophil superoxide anion-generating capacity in hypopituitary adults with GH deficiency

OBJECTIVES

Untreated growth hormone deficiency (GHD) is implicated in the increased cardiovascular risk associated with adult hypopituitarism. Oxidative stress, predisposing to lipid peroxidation, may be an important mediator of endothelial dysfunction, a pro-atherogenic state associated with adult GHD.

DESIGN AND PATIENTS

In a randomized, double-blind, placebo-controlled study we investigated the effects of GH replacement on low-density lipoprotein (LDL) oxidation and neutrophil superoxide (O(-)(2)) generating capacity in 32 GHD adults (19 males, 13 females; age range 19-64 years) over 3 months. Thirty age- and sex-matched healthy controls were also studied.

MEASUREMENTS

Lipid hydroperoxides (HPOs) in plasma were measured using the ferrous oxidation with xylenol orange (FOX) assay. The susceptibility of LDL to oxidation was assessed by the copper-catalysed lag phase of LDL oxidation. Neutrophil O(-)(2)- generating capacity was assessed by a lucigenin-based chemiluminescent assay of NADPH oxidase activity. Body composition was assessed using bioelectrical impedance analysis.

RESULTS

Compared to controls, GHD subjects had higher LDL cholesterol (4.0 +/- 0.8 vs. 3.5 +/- 0.9 mmol/l, P < 0.01) and higher triglyceride concentrations (2.3 +/- 1.5 vs. 1.1 +/- 0.7 mmol/l, P < 0.001) but lower HDL cholesterol (1.1 +/- 0.3 mmol/l vs. 1.4 +/- 0.4 mmol/l, P < 0.01), lower levels of HPOs (0.72 +/- 0.35 vs. 0.92 +/- 0.20 microm, P < 0.01) and lower basal (2.5 +/- 1.5 vs. 4.5 +/- 2.3 mV/5 x 10(5) neutrophils, P < 0.01) and peak post-activation levels (23.2 +/- 11.1 vs. 34.4 +/- 15.6 mV/5 x 10(5) neutrophils, P < 0.01) of neutrophil O(-)(2)- generation. GH replacement resulted in an increase in HPOs from 0.70 +/- 0.39 to 0.86 +/- 0.19 microm (P < 0.05), although there was no change in the lag time of LDL oxidation. Neutrophil O(-)(2)- generating capacity was enhanced with a rise in basal O(-)(2)- generation from 2.8 +/- 1.4 to 5.4 +/- 4.6 mV/5 x 10(5) neutrophils (P < 0.05) and in peak post-activation O(-)(2)- generation from 21.9 +/- 9.5 to 35.8 +/- 21.7 mV/5 x 10(5) neutrophils (P < 0.05). LDL cholesterol was reduced from 4.1 +/- 0.8 mmol/l to 3.5 +/- 0.8 mmol/l (P < 0.01). No significant changes in measured parameters occurred in the placebo group.

CONCLUSIONS

Adult GHD is associated with reduced lipid peroxidation and impaired neutrophil O(-)(2)- generating capacity, both of which are reversible with GH replacement. Our data suggest that: (i) that oxidative stress is not a major feature of the pro-atherogenic state in hypopituitary adults with GHD and (ii) a role for GH in modulating neutrophil function and leucocyte-lipoprotein interactions.

Molecular targets of vertebrate segmentation: two mechanisms control segmental expression of Xenopus hairy2 during somite formation

Vertebrate hairy genes are expressed in patterns thought to be readouts of a "segmentation clock" in the presomitic mesoderm. Here we use transgenic Xenopus embryos to show that two types of regulatory elements are required to reconstitute the segmental pattern of Xenopus hairy2. The first is a promoter element containing two binding sites for Xenopus Su(H), a transcriptional activator of Notch target genes. The second is a short sequence in the hairy2 3' untranslated region (UTR), which most likely functions posttranscriptionally to modulate hairy2 RNA levels. 3' UTRs of other hairy-related, segmentally expressed genes can substitute for that of hairy2. Our results demonstrate a novel mechanism regulating the segmental patterns of Notch target genes and suggest that vertebrate segmentation requires the intersection of two regulatory pathways.

The effects of induced hypogonadism on arterial stiffness, body composition, and metabolic parameters in males with prostate cancer

Sex hormones appear to play a pivotal role in determining cardiovascular risk. Androgen deprivation therapy for males with prostate cancer results in a hypogonadal state that may have important, but as yet undetermined, effects on the vasculature. We studied the effects of androgen deprivation therapy on large artery stiffness in 22 prostate cancer patients (mean age, 67 +/- 8 yr) over a 6-month period. Arterial stiffness was assessed using pulse-wave analysis, a technique that measures peripheral arterial pressure waveforms and generates corresponding central aortic waveforms. This allows determination of the augmentation of central pressure resulting from wave reflection and the augmentation index, a measure of large artery stiffness. Body compositional changes were assessed using bioelectrical impedance analysis. Fasting lipids, glucose, insulin, testosterone, and estradiol were measured. After a 3-month treatment period, the augmentation index increased from 24 +/- 6% (mean +/- SD) at baseline to 29 +/- 9% (P = 0.003) despite no change in peripheral blood pressure. Timing of wave reflection was reduced from 137 +/- 7 to 129 +/- 10 msec (P = 0.003). Fat mass increased from 20.2 +/- 9.4 to 21.9 +/- 9.6 kg (P = 0.008), whereas lean body mass decreased from 63.2 +/- 6.8 to 61.5 +/- 6.0 kg (P = 0.016). There were no changes in lipids or glucose during treatment. Median serum insulin rose from 11.8 (range, 5.6-49.1) to 15.1 (range, 7.3-83.2) mU/liter at 1 month (P = 0.021) and to 19.3 (range, 0-85.0 mU/liter by 3 months (P = 0.020). There was a correlation between the changes in fat mass and insulin concentration over the 3-month period (r = 0.56; P = 0.013). In a subgroup of patients whose treatment was discontinued after 3 months, the augmentation index decreased from 31 +/- 7% at 3 months to 29 +/- 5% by 6 months, in contrast to patients receiving continuing treatment in whom the augmentation index remained elevated at 6 months compared with baseline (P = 0.043). These data indicate that induced hypogonadism in males with prostate cancer results in a rise in the augmentation of central arterial pressure, suggesting large artery stiffening. Adverse body compositional changes associated with rising insulin concentrations suggest reduced insulin sensitivity. These adverse hemodynamic and metabolic effects may increase cardiovascular risk in this patient group.

Intra- and interobserver measurement variability of tibial plateau slope from lateral radiographs in dogs

Measurement of the tibial plateau slope from lateral hind-limb radiographs is a preoperative requirement when performing tibial plateau leveling osteotomy (TPLO) for repair of the cruciate-deficient stifle in dogs. Two measurements of the tibial plateau slope in 312 stifles of 156 dogs were taken from lateral radiographs by each of three observers with varying degrees of experience in the measurement method. Intraobserver variability was +/-3.4 degrees, and interobserver variability was +/-4.8 degrees. No significant differences were identified for the intraobserver measurements; however, in evaluating interobserver variability, a significant difference was found between the inexperienced observer and the two experienced observers.

Cancrum oris in a Caucasian male with Type 2 diabetes mellitus

We describe a patient with Type 2 diabetes mellitus who developed cancrum oris requiring extensive oro-facial reconstructive surgery. There are no previous published reports of cancrum oris occurring in a Caucasian subject with no risk factors other than Type 2 diabetes.

Traumatic brain injury elevates the Alzheimer's amyloid peptide A beta 42 in human CSF. A possible role for nerve cell injury

The increased risk for Alzheimer's Disease (AD) associated with traumatic brain injury (TBI) suggests that environmental insults may influence the development of this age-related dementia. Recently, we have shown that the levels of the beta-amyloid peptide (A beta 1-42) increase in the cerebrospinal fluid (CSF) of patients after severe brain injury and remain elevated for some time after the initial event. The relationships of elevated A beta with markers of blood-brain barrier (BBB) disruption, inflammation, and nerve cell or axonal injury were evaluated in CSF samples taken daily from TBI patients. This analysis reveals that the rise in A beta 1-42 is best correlated with possible markers of neuronal or axonal injury, the cytoskeletal protein tau, neuron-specific enolase (NSE), and apolipoprotein E (ApoE). Similar or better correlations were observed between A beta 1-40 and the three aforementioned markers. These results imply that the degree of brain injury may play a decisive role in determining the levels of A beta 1-42 and A beta 1-40 in the CSF of TBI patients. Inflammation and alterations in BBB may play lesser, but nonetheless significant, roles in determining the A beta level in CSF after brain injury.

A therapeutic trial of growth hormone in hypopituitary adults and its influence upon continued prescription by general practitioners

OBJECTIVES

Adult GH deficiency (GHD) is associated with profound alterations in body composition, lipid profiles and quality of life which frequently improve after GH therapy. However, the beneficial effects of treatment are not derived by all and consequently some scepticism persists with regard to the use of GH therapy in adults. We assessed whether a 3-month therapeutic assessment with GH therapy could be used to determine which GHD adults should be treated over the longer term. We also assessed the continued prescription of GH by general practitioners (GPs) following the initial therapeutic assessment.

DESIGN

A three month open therapeutic trial of GH in GHD adults. Patients were treated with GH at an initial dose of 0.01 iU/kg/d, increased after 1 month to 0.015 iU/kg/d for males and 0.02 iU/kg/d for females. After completion of the three months the continued prescription of GH by the GPs was assessed.

PATIENTS

All adult GHD patients were considered for GH therapy. Thirty-nine GHD adults wanted GH therapy (group 1) and their baseline characteristics such as age, duration of GHD, and IGF-1 concentration were compared with 24 subjects who declined to receive GH (group 2).

MEASUREMENTS

Measurements of body composition using bioelectrical impedance analysis, lipids and quality of life measured using a dedicated questionnaire were made before and after GH therapy. The response of the general practitioners to continued GH therapy after the initial therapeutic assessment was also noted.

RESULTS

Compared with subjects who declined GH therapy (group 2), subjects of group 1 were younger (46.4 +/- 14.4 vs. 54.2 +/- 15.7 years, P < 0.05) and had lower peak GH responses to provocative testing (1.4 +/- 2.1 vs. 2.9 +/- 2.7 mU/l, P < 0.001), though there were no differences between IGF-1 concentration (11.7 +/- 6.2 vs. 14. 2 +/- 7.9 nmol/l). Following three months of GH therapy, there were significant improvements in all measured parameters including increased free fat mass (50.2 vs. 52.4 kg, P < 0.005) and total body water (37 vs. 38.7 l, P < 0.005), reduced fat mass (31.6 vs. 29.8 kg, P < 0.005), reduced AGHDA score (7 vs. 4, P < 0.001) and reduced cholesterol (6.3 vs. 5.8 mmol/l, P < 0.001), LDL (4 vs. 3.33 mmol/l, P < 0.001) and cholesterol/HDL ratio (5.57 vs. 4.67, P < 0.001). IGF-1 concentrations were significantly increased following treatment (12 vs. 32.4 nmol/l). Six subjects decided to discontinue GH therapy, 2 before the end of the study due to potential drug-related side-effects and 4 subjects derived no benefit from treatment. Despite the demonstrable benefits of treatment for the remaining 33 GHD adults, 6 GPs refused to continue to prescribe GH therapy for reasons of lack of familiarity with the drug or advice from their health authority.

CONCLUSION

Patients who wanted GH therapy were usually younger and more severely GHD than counterparts who elect not to be treated. However, a therapeutic trial of GH therapy is required to distinguish those subjects who derive benefit from treatment. We have shown that three months of low dose GH therapy is a sufficient period to elicit significant beneficial responses in quality of life, body composition parameters and lipids for the majority of patients and appears to be a sufficient period for patients to decide whether they want longer term therapy. The initial therapeutic trial also provides the objective evidence for the general practitioners to decide upon the continued prescription of therapy. Despite the positive evidence provided by this study, a small minority of general practitioners still refuse to prescribe GH therapy.

The effect of GH replacement therapy on endothelial function and oxidative stress in adult growth hormone deficiency

OBJECTIVES

Controversy persists with regard to the atherogenic risk associated with adult growth hormone deficiency (GHD). Endothelial dysfunction and enhanced oxidative stress are early features of atherogenesis. Therefore, we have studied the effect of three months of low dose GH replacement therapy (0.03IU/kg/day) on these parameters in GHD adults.

SUBJECTS AND METHODS

Eight hypopituitary GHD adults (4 male, 4 female), who were receiving conventional hormone replacement therapy, were studied before and after 3 months of GH replacement (0.03IU/kg/day). All observations obtained were compared with similar measurements made in 8 matched control subjects. All study subjects were non-smokers, normotensive and gave no personal or family history of premature vascular disease. Endothelial function was assessed using a specialised vessel wall tracking system to measure endothelium-dependent, flow-mediated, brachial artery dilatation (FMD). Measurements were repeated following glyceryl-trinitrate (GTN) (endothelium-independent dilatation). Oxidative stress was assessed by directly measuring lipid-derived free radicals in venous blood by electron paramagnetic resonance spectroscopy. Fasting lipids, insulin, plasma glucose and IGF-I were also measured at baseline and following GH replacement.

RESULTS

FMD, expressed as a percentage change from resting base-line diameter, was significantly impaired in the pre-treatment GHD patients compared with controls (3.1+/-2.1% vs 6.1+/-0.9%, P<0. 001; means+/-s.d.) indicating endothelial dysfunction. Significant increase in FMD was noted following GH therapy (3.1+/-2.1% vs 6. 5+/-1.9%, P<0.001). Free radicals (arbitrary units) were elevated in the pre-treatment GHD patients compared with controls (0.36+/-0.09 vs 0.11+/-0.12, P<0.05) and fell significantly following GH therapy (0.23+/-0.03 vs 0.36+/-0.09, P<0.05), although they remained elevated compared with controls. Fasting insulin was significantly higher (25.9+/-18.8 vs 13.9+/-6.7mu/l, P<0.05) and IGF-I concentrations lower (10.8+/-4.7 vs 20.2+/-6.3nmol/l, P<0.05) in the pre-treatment GHD subjects. After treatment there were no changes in insulin concentration, although IGF-I levels were normalised (10. 8+/-2.3 vs 23.6+/-11.4nmol/l, P<0.05).

CONCLUSIONS

Endothelial dysfunction and enhanced oxidative stress are features of adult GHD. This study suggests plausible mechanisms underlying any proatherogenic tendency in adult GHD and demonstrates improvement of these factors following GH replacement.

Endothelial dysfunction in hypopituitary adults with growth hormone deficiency

OBJECTIVES

Adult hypopituitarism with growth hormone deficiency (GHD) results in reduced exercise capacity, detrimental changes in body composition and lipid profiles and may be associated with an excess cardiovascular mortality. Endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and predisposes to the deposition of unstable atherosclerotic plaques. We have used a noninvasive method to assess endothelial function in the brachial arteries of a group of treated hypopituitary adults with GHD, and a group of healthy age- and sex-matched controls.

PATIENTS

Seventeen hypopituitary adults with GHD (13 male, 4 female) aged 26-54 years were studied. Each patient was receiving standard replacement therapy for all other hormonal deficiencies such that all target hormones were maintained in the normal reference range. All observations obtained were compared with those made in age- and sex-matched control subjects. All study subjects had no identifiable risk factors for endothelial dysfunction.

MEASUREMENTS

Using an ultrasound vessel wall tracking system, the diameter of the left brachial artery was measured at rest, in response to reactive hyperaemia (endothelium-dependent dilation) and following sublingual glyceryl trinitrate (GTN) (endothelium-independent vasodilatation). We also measured fasting lipids, insulin, plasma glucose, glycated haemoglobin (HbA1c) and IGF-1, and studied the relationship of these parameters to endothelial function.

RESULTS

Flow mediated endothelium-dependent dilatation (FMD), expressed as a percentage change from resting base-line diameter, was significantly impaired in the GHD group (3.70 +/- 2.36% vs. 7.30 +/- 2.42%, P < 0.001). In contrast, GTN-mediated dilatation was similar in both groups. There were no differences in total cholesterol, HDL cholesterol, LDL cholesterol or plasma triglyceride between the groups. Both fasting insulin (27.1 +/- 18.1 vs. 15.89 +/- 6.65 mU/l, P < 0.05) and glycated haemoglobin (HbA1c) levels (5.29 +/- 0.43 vs. 4.91 +/- 0.43%, P < 0.05) were significantly higher in the GHD group. FMD in both groups showed an inverse relationship with total cholesterol (r = -0.58, P < 0.05, GHD and r = -0.55, P < 0.05 controls). However, in the GHD subjects, there was a strong inverse relationship between FMD and LDL-cholesterol (r = -0.81, P < 0.0001). No other relationships were noted between FMD and any other metabolic parameters, or characteristics of GHD.

CONCLUSIONS

Endothelial dysfunction is present in GH deficient adults prior to the onset of overt atherosclerotic disease. The similar glucose yet elevated fasting insulin levels imply a state of relative insulin insensitivity. The strong inverse correlation between endothelial dysfunction and LDL-cholesterol suggests a possible aetiological role for LDL-cholesterol in the pathogenesis of any excess cardiovascular risk associated with adult hypopituitarism.

Benzenesulfonamide derivatives of 2-substituted 4H-3,1-benzoxazin-4-ones and benzthiazin-4-ones as inhibitors of complement C1r protease

A series of 2-sulfonyl-4H-3,1-benzoxazinones was prepared that inhibit C1r protease in vitro. Several compounds were found to be selective for C1r verses the related serine protease trypsin. Selected compounds demonstrated functional activity in a hemolysis assay.

A Low Protein, High Carbohydrate Diet Attenuates Alcohol Intake in Rats

To test whether a tryptophan-enhancing diet will reduce alcohol intake as serotonergic drugs do, two studies were conducted. In Experiment 1, 32 male, alcohol-drinking rats were randomly assigned to one of four isocaloric diets containing 25%-protein/65%-carbohydrate, 25%-protein/4%-carbohydrate, 4%-protein/65%-carbohydrate, or 4%-protein/4%-carbohydrate. Following a baseline week during which they ate standard lab chow, rats were offered their assigned experimental diet, water, and 5%-alcohol solution ad lib for three weeks. Alcohol and diet intakes were measured daily. In Experiment 2, 32 naive male, alcohol-drinking rats were assigned to one of the experimental diets used in Experiment 1. Following a one-week baseline, rats were offered their assigned diet, water, and 5%-alcohol/1%-sucrose solution ad lib for two weeks and then were switched back to standard lab chow for one week, with alcohol intake measured daily. Rats consuming the low protein, high carbohydrate diet drank 60-80% less alcohol than did rats offered other diets. This reduction in alcohol intake is most likely due to increased brain serotonin levels produced by the dietary manipulation.

Traumatic brain injury increases beta-amyloid peptide 1-42 in cerebrospinal fluid

The beta-amyloid peptides, A beta1-42 and A beta1-40, were quantified in ventricular CSF taken daily for up to 3 weeks from six individuals with severe traumatic brain injury (TBI). There was considerable interindividual variability in the levels of A beta peptides, but in general A beta1-42 levels equalled or exceeded those of A beta1-40. Averaging the daily totals of our trauma cohort revealed that the levels of A beta1-42 and A beta1-40 rose after injury, peaking in the first week and then declining toward control levels over the next 2 weeks. A beta1-42 levels were on average two to three times higher in the trauma cohort than in CSF from nontrauma samples. Compared with nontrauma samples, the A beta1-40/A beta1-42 ratio decreased about fivefold in the trauma patients, further indicative of increased A beta1-42 levels. The ratio remained low at all time points studied. No change was measured in the levels of beta-amyloid precursor protein during the same interval. These results suggest that A beta1-42 becomes elevated in the CSF after severe brain trauma.

Geminin, a neuralizing molecule that demarcates the future neural plate at the onset of gastrulation

In an expression cloning screen in Xenopus embryos, we identified a gene that when overexpressed expanded the neural plate at the expense of adjacent neural crest and epidermis. This gene, which we named geminin, had no sequence similarity to known gene families. We later discovered that geminin's neuralizing domain was part of a bifunctional protein whose C-terminal coiled-coil domain may play a role in regulating DNA replication. We report here on the neuralizing function of geminin. The localization, effect of misexpression and activity of a dominant negative geminin suggest that the product of this gene has an essential early role in specifying neural cell fate in vertebrates. Maternal geminin mRNA is found throughout the animal hemisphere from oocyte through late blastula. At the early gastrula, however, expression is restricted to a dorsal ectodermal territory that prefigures the neural plate. Misexpression of geminin in gastrula ectoderm suppresses BMP4 expression and converts prospective epidermis into neural tissue. In ectodermal explants, geminin induces expression of the early proneural gene neurogenin-related 1 although not itself being induced by that gene. Later, embryos expressing geminin have an expanded dorsal neural territory and ventral ectoderm is converted to neurons. A putative dominant negative geminin lacking the neuralizing domain suppresses neural differentiation and, when misexpressed dorsally, produces islands of epidermal gene expression within the neurectodermal territory, effects that are rescued by coexpression of the full-length molecule. Taken together, these data indicate that geminin plays an early role in establishing a neural domain during gastrulation.

Sizzled: a secreted Xwnt8 antagonist expressed in the ventral marginal zone of Xenopus embryos

An expression cloning screen was used to isolate a novel gene homologous to the extracellular cysteine-rich domain of frizzled receptors. The gene (which we called sizzled for secreted frizzled) was shown to encode a soluble secreted protein, containing a functional signal sequence but no transmembrane domains. Sizzled (szl) is capable of inhibiting Xwnt8 as assayed by (1) dose-dependent inhibition of siamois induction by Xwnt8 in animal caps, (2) rescue of embryos ventralized by Xwnt8 DNA and (3) inhibition of XmyoD expression in the marginal zone. Szl can dorsalize Xenopus embryos if expressed after the midblastula transition, strengthening the idea that zygotic expression of wnts and in particular of Xwnt8 plays a role in antagonizing dorsal signals. It also suggests that inhibiting ventralizing wnts parallels the opposition of BMPs by noggin and chordin. szl expression is restricted to a narrow domain in the ventral marginal zone of gastrulating embryos. szl thus encodes a secreted antagonist of wnt signaling likely involved in inhibiting Xwnt8 and XmyoD ventrally and whose restricted expression represents a new element in the molecular pattern of the ventral marginal zone.

Polycythemia vera in a cat and management with hydroxyurea

Polycythemia vera (PV) was diagnosed in a four-year-old domestic shorthair evaluated for hind-limb ataxia, extension of all claws, and difficulty in jumping to elevated surfaces. Mild cardiac hypertrophy also was diagnosed. Initial laboratory evaluation revealed polycythemia (packed cell volume [PCV], 75%) and normal serum total protein (7.5 g/dl). Definitive diagnosis of PV was reached by excluding causes of relative and secondary absolute polycythemia using radiography, ultrasonography, and blood gases, and by measuring serum erythropoietin concentration by radioimmunoassay (13 mU/ml) and an enzyme-linked immunosorbent assay (ELISA) method (8.0 mU/ml). Bone-marrow biopsy revealed relative erythroid hyperplasia characteristic of myeloproliferative disease. Clinical signs were controlled with hydroxyurea (12.2 mg/kg body weight) and occasional phlebotomy. Polycythemia vera is an uncommon feline disease, and clinical reports on the use of hydroxyurea to manage the condition in the cat are lacking.

Loss of interferon antibodies during prolonged continuous interferon-alpha 2a therapy in hairy cell leukemia

Although highly active in hairy cell leukemia (HCL), interferons (IFN) are not curative in this disease; current data indicate that prolonged IFN therapy will be necessary to control disease in the majority of patients. We previously observed acquired IFN resistance in association with neutralizing IFN-alpha 2a antibodies in small numbers of patients with HCL. This finding suggests that the requisite long-term therapy may be compromised if there is an increasing incidence over time of neutralizing antibodies. We performed a follow-up study of IFN antibodies in our patients receiving continuous IFN therapy. All 16 patients who were previously antibody negative remained so. Surprisingly, all nine patients who previously had non-neutralizing IFN antibodies became antibody negative after a median of 14.5 months. Moreover, 3 of 10 patients who had neutralizing antibodies became antibody negative and five had only non-neutralizing antibodies a median of 10 months from the time neutralizing antibody had first been detected. Only two patients had persisting neutralizing antibodies. Inhibition of neopterin synthesis, inhibition of generation of 2', 5' oligoadenylate synthetase activity, and inability to detect IFN in serum after subcutaneous injection of IFN-alpha 2a was observed only in the one patient tested with neutralizing IFN antibodies confirming that these antibodies have functional significance in vivo. We conclude that, although neutralizing IFN antibodies inhibit the effectiveness of IFN in vivo, these antibodies are produced only transiently during long-term therapy. The long-term effectiveness of this drug will not likely be affected in most patients by neutralizing antibody.

Interferon-alpha 2a in the treatment of acquired immunodeficiency syndrome-related Kaposi's sarcoma

In a series of studies, recombinant interferon-alpha 2a (rIFN alpha 2a, Roferon-A) was administered alone (273 men) or combined with vinblastine (91 men) to patients with acquired immunodeficiency syndrome (AIDS)-related Kaposi's sarcoma (KS). Patients were treated with daily doses of rIFN alpha 2a ranging from 3 to 54 million international units (I.U.) administered intramuscularly. A dose of 36 million I.U. daily for approximately 10 weeks followed by a three times weekly maintenance schedule with the same dose resulted in the best overall therapeutic benefit. An escalating-dose regimen of 3, 9, and 18 million I.U. daily, each for 3 days, followed by 36 million I.U. daily, produced equivalent therapeutic benefit with amelioration of acute toxicity in some patients. Response was more likely in patients without a history of opportunistic infection or B symptoms (fever, night sweats, or weight loss). Response rate increased with increasing baseline CD4 lymphocyte count and was 45.5% in patients with a CD4 count of greater than 400/mm3. Responding patients with a CD4 count of greater than 200/mm3 had a distinct survival advantage over patients who had similar CD4 counts but whose tumors did not regress with therapy. The addition of vinblastine increased toxicity and did not improve the response rate or prolong survival. Side effects included fatigue, fever, chills, myalgias, headaches, anorexia, nausea, diarrhea, and dizziness. Mild abnormalities in hematologic and liver function tests occurred in some patients. Most adverse effects diminished or resolved with continued therapy. We conclude that rIFN alpha 2a offers important therapeutic benefit in a select group of patients with AIDS-related KS.

Phosphatidylinositol-specific phospholipase C of Bacillus cereus: cloning, sequencing, and relationship to other phospholipases

The phosphatidylinositol (PI)-specific phospholipase C (PLC) of Bacillus cereus was cloned into Escherichia coli by using monoclonal antibody probes raised against the purified protein. The enzyme is specific for hydrolysis of the membrane lipid PI and PI-glycan-containing membrane anchors, which are important structural components of one class of membrane proteins. The protein expressed in E. coli comigrated with B. cereus PI-PLC in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, as detected by immunoblotting, and conferred PI-PLC activity on the host. This enzyme activity was inhibited by PI-PLC-specific monoclonal antibodies. The nucleotide sequence of the PI-PLC gene suggests that this secreted bacterial protein is synthesized as a larger precursor with a 31-amino-acid N-terminal extension to the mature enzyme of 298 amino acids. From analysis of coding and flanking sequences of the gene, we conclude that the PI-PLC gene does not reside next to the gene cluster of the other two secreted phospholipases C on the bacterial chromosome. The deduced amino acid sequence of the B. cereus PI-PLC contains a stretch of significant similarity to the glycosylphosphatidylinositol-specific PLC of Trypanosoma brucei. The conserved peptide is proposed to play a role in the function of these enzymes.

Incidence and clinical significance of neutralizing antibodies in patients receiving recombinant interferon-alpha 2a

In clinical trials with a range of doses of recombinant interferon-alpha 2a, we observed a 25% overall incidence of neutralizing antibody development. Careful data analysis did not reveal a relationship between antibody development and therapeutic response. Of 752 patients evaluable for antibody development and clinical response, 31% of the antibody-positive patients and 28% of the antibody-negative patients had therapeutic responses. Although the formation of anti-IFN antibodies seems to be associated with most IFN preparations, incidence and clinical significance have been difficult to determine for a number of reasons. Different assays with differing sensitivities for the detection of IFN antibodies have been utilized in different studies. Additionally, important clinical variables that affect antibody development have often not been carefully controlled or analyzed. The relationship between antibody development and multiple related factors, such as route of administration, dose regimen, cumulative dose, duration of treatment, and the underlying disease, requires clarification. Initial analyses suggest that the median time to antibody development may vary with the dose regime and cumulative dose, as well as the route of administration. Carefully designed prospective studies controlling for influential clinical variables and utilizing standardized assay techniques are required for a meaningful analysis of the antigenic potential of all therapeutic protein products.

Phosphatidylinositol-specific phospholipase C from Bacillus cereus: improved purification, amino acid composition, and amino-terminal sequence

Phosphatidylinositol-specific phospholipase C was purified in a 27% yield from the culture medium of Bacillus cereus by a combination of ammonium sulfate precipitation and ion-exchange and hydrophobic interaction chromatography. The purified enzyme was free of other phospholipase C-type activities and exhibited a high specific activity of approximately 1,300 units/mg. Amino acid composition analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a molecular weight of about 35 kDa. The sequence of the first 29 N-terminal amino acids was also determined.

Resistance to recombinant interferon alfa-2a in hairy-cell leukemia associated with neutralizing anti-interferon antibodies

To explain the hematologic deterioration occasionally observed during interferon therapy, we assayed serum specimens from 51 patients with hairy-cell leukemia receiving treatment with recombinant interferon alfa-2a for the presence of anti-interferon antibodies. After a median of seven months of therapy, anti-interferon antibodies were found in 31 patients. Fifteen of these patients had only non-neutralizing antibodies, but antibody from the other 16 neutralized the antiviral effects of recombinant interferon alfa-2a in vitro. In no case, however, did neutralizing antibody inhibit the antiviral effects of purified natural interferon alfa. Clinical resistance to interferon of various degrees was present in 6 of 16 patients with neutralizing antibodies; the remaining 10 patients and all 20 patients without antibody continue to respond after a minimum of two years of therapy. In all the patients with interferon resistance, antibody was present when it developed. These data suggest that the development of clinical resistance to interferon alfa-2a in hairy-cell leukemia is not necessarily related to an altered cellular response to interferon. Treatment with other interferons, such as purified natural interferon alfa, may be useful in patients with clinically important neutralizing antibodies against interferon alfa-2a.

Clinical evaluation of recombinant interferon alfa-2a (Roferon-A) in metastatic melanoma using two different schedules

Based on the reports of activity of interferons against metastatic melanomas, we conducted a phase II study of recombinant interferon alfa-2a (Roferon-A, Hoffmann-La Roche, Nutley, NJ) in 66 patients with disseminated melanoma. All patients had excellent Eastern Cooperative Oncology Group (ECOG) performance status (0 to 1), and no evidence of brain metastases. Thirty patients had previously received chemotherapy and the remainder were untreated. The first 35 patients were treated on a daily schedule starting with a Roferon-A dose of 3 X 10(6) U/d and escalating to a maximum of 36 X 10(6) U/d over a period of 12 days. Because of excessive toxicity, the second group of 31 patients were treated on a fixed dose of 18 X 10(6) U/d [corrected] three times weekly (TIW). Among the 62 evaluable patients, five achieved an objective response for a response rate of 8% (95% confidence limits, 3% to 18%). Four patients had minor regressions and eight patients had stability of disease. The responses were evenly distributed between the two dose schedules. The major toxicity of interferon consisted of a constitutional syndrome of anorexia, fever, weight loss, and fatigue, which required a dose reduction in 75% of the patients on the daily schedule. Our data revealed a modest level of activity, which was not influenced by prior treatment or by the dose or schedule of interferon. Because of substantial toxicity with the daily schedule, we recommend a dose of 18 X 10(6) U/d [corrected] if interferon is used in the treatment of patients with melanoma.

Phase II trial of carboplatin in advanced malignant melanoma

Twenty-six evaluable patients with metastatic malignant melanoma who had not received prior chemotherapy were treated in a phase II study with carboplatin (CBDCA), 400 mg/m2 iv every 4 weeks. There were five partial responses of 3, 3+, 5, 7+, and 12+ months' duration. Thrombocytopenia was the dose-limiting toxicity; ten patients had transient platelet count depressions to less than 75,000/mm3. Mild to moderate nausea and/or vomiting occurred in 15 patients. Renal, auditory, and neurologic toxic effects were not encountered. Since the response rate of 19% (95% confidence limits, 8%-38%) is similar to that noted for dacarbazine, carboplatin, singly and in combination with other agents, needs further evaluation in patients with malignant melanoma.